PITTSFIELD, Mass. (WWLP) – The Pittsfield police officer who shot and killed a man while responding to a domestic violence call last September will not be facing criminal charges.

According to Berkshire County District Attorney David Capeless’ Office, their investigation has determined that Officer Christopher Colello acted lawfully in defense of his fellow officers when he shot and killed 36-year-old Daniel Gillis.

“The entire incident developed within a short period of time and rapidly escalated when Gillis emerged from the house holding a knife to his throat and advanced upon officers despite their calls to drop the knife,” Capeless said. “When Gillis suddenly changed direction and charged at several officers, yelling at them, the situation changed from dangerous to life-threatening.”

The DA’s office used cell phone video taken by a neighbor has part of their investigation.

“The investigation involved multiple, extended interviews of the many participants and witnesses, but the few seconds of the real-time capture of the event provided the most informative piece of the investigation,” Capeless said.